| Soil heavy metal pollution poses a great threat to agricultural environment.It was becoming to the focus of current study because of the serious farmland environment and agricultural product quality.Under environmental pollution,the acid precipitation and rainwater-borne hydrogen peroxide(H2O2)is widespread present in soil-water system.Furthermore,acid and oxidation precipitation(H2O2)has the capacity to redox reactions with soil environmental heavy metal cation and leads to influence of heavy metal pollutants transport,transformation,and fate end.In addition,biochar has been mainly used to soil carbon sequestration,fertility improvement and pollution remediation.In this study,the pot experiment and plot field experiment were conductedto examine the effectsof the iron modified biochar(Fe BC)and ordinary biochar(BC)on the growth of andtrace element uptake by peanut plants under simulated acid rain(p H=4.3)and oxidant(50?M H2O2)precipitation conditions.Main results were shown as follows:1.The first pot experiment exploredthe effects of different biochar on peanutgrown and arsenic,cadmium accumulation under acid and oxidation precipitation.Results showed thatacid and oxidation precipitations had nosignificant differenceof the peanut biomass,nodule number and dry weight of nodule,chlorophyll content(SPAD)and chlorophyll fluorescence.However,there was significant increased Cd accumulation on seed and As accumulation on shelland root portion.By comparison,the peanut biomass,nodule number and dry weight of nodule and SPAD were significantly less in the biochar(iron modified biochar(Fe BC)and ordinary biochar(BC))treatment than CK.But the Fe BC treatment increased nodule number and dry weight of nodule of peanut under acid and oxidation precipitations than BC and CK.the concentration of As and Cd on all parts of peanut except a slight increase of As in seed were significantly less in the Fe BC treatment than BC and CK.2.The second pot experiment exploredthe effects of iron modified biochar(Fe BC)on physiological ecology of peanut seedlings under acid and oxidation precipitation.Results showed that the SPAD of peanut was significantly less in acid precipitation(S)treatment than other precipitations(W,H,S&H),whereas the photosynthesis was opposite.The activity of SOD and MDA were significantly higher in oxidation precipitation(H)treatment than other precipitations.And in the 3%Fe BCtreatment,The activity of C AT and photosyntheticrate were significantly higher in Wand S precipitations treatment than H and S&Hprecipitations.But the content of MDA was on the contrary.By comparison,the SPAD,photosyntheticrateand the activity of SOD were significantly higher and thestomatalconductanceandintercellular CO2 concentration were significantly less in Fe BC treatment than CK.3.A plot field experiment was conducted to studythe effects of iron modified biochar(Fe BC)on growth dynamics,yield and cadmium accumulation of peanut under acid and oxidation precipitation.Results showed that acid and oxidation precipitations had no significant differenceof the peanut growth(biomass,root length a nd plant height of peanut).However,there were significant increased the yield of peanut(the number of full pods and the weight of pods)and Cd accumulation on root,seed and shellportion.The Cd concentration on above-ground and seed portion under W precipitation were less in Fe BC treatment than CK.In the maintime,the Cd concentration on all parts of peanut under acid and oxidation precipitations was reduced in Fe BC treatment,especially under the acid precipitation.This study demonstrated that acid and oxidation precipitations had nosignificant differenceof the peanut growth.But the yield and the ab sorption of As and Cd in peanut were improved.The application of Fe BC alleviated the toxic effect of As and Cd to peanut under acid and oxidation precipitations,in particular reducing the accumulation of As and Cd in peanut under acid precipitation. |
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